Gasketed watertight segmented tunnel linings

ABSTRACT

A segmented primary tunnel lining is provided having longitudinal and circumferential bolted joints in which an elastic gasket is placed between corresponding jointed flanges of the circumferential joints and between the corresponding jointed end plates of the longitudinal joints. The flanges and end plates are deformed by high strength bolts to exhibit metal-to-metal contact in the area of the bolts for joint stiffness. The gaskets are positioned to the outside of the bolts for prevention of leaks.

United States Patent Platner et a1.

[ Jan. 14, 1975 GASKETED WATERTIGHT SEGMENTED TUNNEL LININGS Assignee:

Filed:

Inventors: James B. Platner, Severna Park;

Charles M. Schaefer, 1111, Baltimore, both of Md.

Bethlehem Steel Corporation,

Bethlehem, Pa.

June 20, 1973 Appl. N0.: 371,915

U.S. Cl 61/45 R Int. Cl E2ld 11/14 Field of Search 61/45 R, 42, 85, 84;

References Cited UNITED STATES PATENTS Aims 61/45 R Lennon 61/45 R Woodworth 151/45 R Humphryes 61/45 R 2,783,295 2/1957 Ewing 285/363 X 3,135,538 6/1964 George 285/363 3,214,201 10/1965 Fonda 285/363 3,695,044 10/1972 Hoshino eta1............ 61/45 R 3,707,846 1/1973 Leblond et a1... 61/45 R Primary ExaminerDennis L. Taylor Attorney, Agent, or Firm-Joseph J. OKeefe; Michael J. Delaney; John J. Selko [57] ABSTRACT A segmented primary tunnel lining is provided having longitudinal and circumferential bolted joints in which an elastic gasket is placed between corresponding jointed flanges of the circumferential joints and between the corresponding jointed end plates of the langitudinal joints. The flanges and end plates are deformed by high strength bolts to exhibit metal-tometal contact in the area of the bolts for joint stiffness. The gaskets are positioned to the outside of the bolts for prevention of leaks,

4 Claims, 4 Drawing Figures GASKETED WATERTIGI-IT SEGMENTED TUNNEL LININGS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to segmented tunnel linings and more particularly to water proof segmented primary tunnel linings in which the segments are bolted together and a gasket is used to prevent leaks.

2. Prior Art Primary tunnel linings have in the past been constructed with arcuate segments formed from rolled channels in which the flanges extend in toward the tunnel interior, and end plates are welded between the flanges. An annular tunnel portion is made by bolting together, to form longitudinal joints, the corresponding end plates on adjacent segments. The length of the tunnel is increased by bolting together, to form circumferential joints, the corresponding flanges on adjacent segments.

For proper load carrying characteristics, termed stiffness, the bolted longitudinal and circumferential joints should exhibit metal-to-metal contact between the jointed flanges and end plates of adjacent segments. This configuration does not prevent water or air leaks. In addition, the dimensions of the rolled channels normally vary due to wear of rolls in the rolling mill. This dimensional variance can cause misalignment of adjacent segments, and increases the possibility of leaks.

For the proper freedom from leaks, the longitudinal and circumferential joints have in the past included a gasket between the jointed flanges and end plates. The elastic gasket can compensate for misalignment of segments due to dimensional variations, and can act as a seal between jointed flanges and end plates. A problem with the prior art gasket is that the presence of the gasket in the area of the bolts can permit the bolts to loosen, when the gasket creeps under loading decreasing joint stiffness. Gasket creeping is aggravated under increased loads due to jacking forces associated with advancement of a shield at the front end of the tunnel.

Thus, there is a need for a waterproof gasketed bolted joint which also provides the proper degree of stiffness.

SUMMARY OF THE INVENTION It is an object to provide a waterproof gasketed bolted joint for use in segmented tunnel linings.

It is a further object to provide a waterproof gasketed bolted joint which will not loosen due to creep of the gasket.

It is a further object to provide a waterproof gasketed bolted joint which provides a waterproof joint with a proper degree of joint stiffness.

These and other objects can be obtained by providing longitudinal and circumferential bolted joints in which an elastic gasket is positioned in the joint outside of the bolts, and in which the joints exhibit metal-to-metal contact in the area of the bolts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I shows an annular tunnel portion made from four arcuate segments plus one key segment bolted together.

FIG. 2 shows a perspective view of two adjacent segments bolted together.

FIG. 3 is a view taken along 33 of FIG. 2.

FIG. 4 is a view taken along 4-4 of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENT FIG. 1 shows an annular tunnel portion 1 comprised of four arcuate segments 3 plus one key segment 5 bolted together, as is well known in the art.

FIG. 2 shows segment 3 made with rolled channels 7. Each channel 7 has a web portion '9 and flanges II and 11 which extend toward the interior of the tunnel. We

prefer to make segment 3 a double channel segment by welding two rolled channels together at flanges II and II. By making segment 3 a double channel segment. fewer bolted joints are required in actual tunnel construction. The double channel segment is optional and a single channel will serve as well. End plates 15 and 15 are welded across channels 7 between flanges II and 11, as is well known in the art. Stiffeners 17 are welded between flanges l1 and 11' at appropriate intervals, as is also well known.

A longitudinal joint 19 is made by joining together with high strength bolts 21 and nuts 21 corresponding end plates 15 and 15' of adjoining segments. A circumferential joint 23 is made by bolting together, with high strength bolts 25 and nuts 25', corresponding flanges 11 and 1] of adjacent segments 7.

FIG. 3 shows a circumferential joint 23. Flanges 11 and 11 are bolted together with high strength bolts 25 and nuts 25. Positioned between and in contact with the opposed plane surfaces 26 and 27 of flanges 11 and 11' is elastic gasket 29. Gasket 29 is located outside of bolts 25 adjacent the outer end of flanges l1 and 11. FIG. 1 also shows the location of gasket 29 on flange 11'. Gasket 29 can compensate for slight misalignment of segments 7 and helps make joint 23 waterproof. Because gasket 29 is subject to high compressive loads, due to bolts 25 and subsequentjacking forces, selection of the gasket material is important. We prefer a neoprene having a durometer less than 39 and a tensile strength in excess of 2,000 pounds per square inch.

It is also preferred that the gasket material exhibit low creep, also referred to as compression set. As is well known in the art, creep is measured by compressing an elastic specimen by twenty five percent of its original thickness. After the specimen is released, the amount that it fails to return to its original dimension, expressed as per cent, is a measure of the creep characteristics.

For evaluating the gasket material of the invention, a more severe test was employed, in which the specimen was compressed by seventy five percent rather than the usual twenty five percent. Under a seventy five percent compression test, the preferred gasket material exhibited less than ten percent set, or creep.

These preferred properties are found in a neoprene conforming to the National Association of Architectural Metals Manufacturing Specifications for Dense Rubber-Like Compression Gasket. Materials, referred to as NAAMM Standard SG-1-70.

Gasket 29 can be attached with suitable adhesive to flange 11' prior to shipment, so gasket 29 is properly positioned.

Bolt 25 is of the high strength type well known in the art, and is tightened enough to cause joint 23 to be a friction joint. In a friction joint, stiffness of joint 23 is enhanced due to friction between opposed plane surface 26 and 27.

Flanges 11 and 11 are deformed due to tightening of bolt 25 and joint 23 derives stiffness from the metal-tometal contact between the opposed plane surfaces 26 and 27 of flanges 11 and 11' in the area of the bolt 25 on into the inner end of flanges 11 and 11.

FIG. 4 shows a longitudinal joint 19. Endplates l5 and are welded to web 9. End plates 15 and 15 are joined with high strength bolt 21 and nut 21'. Positioned between and in contact with opposed plane surfaces 31 and 32 of end plates 15 and 15' is gasket 33 of the same material as the gasket 29. Gasket 33 is located toward the outside of bolt 21 adjacent the outer end of end plates 15 and 15. Gasket 33 is fastened to end plate 15 in the same manner as gasket 29 is attached to flange 11.

End plates 15 and 15 are deformed by high strength bolt 21 and nut 21, and joint 19 derives stiffness from the metal-to-metal contact between opposed plane surfaces 31 and 32 in the area of the bolt 21 on into the inner end of end plate 15 and 15'.

In actual practice we have successfully assembled and water tested a section of ten foot diameter tunnel liner embodying the invention. Three annular tunnel portions 1 were boltjointed from segments 3. Each segment 3 was a double channel segment made by welding together at corresponding flanges flanges 11 and 11 two single channel segments are previously described. Each rolled channel 7 was made from A.S.T.M. A-36 steel and was a miscellaneous channel 18 inches wide with flanges 11 and 11 4 inches high with a weight per foot of 42.7 pounds. Sections 7 were bent to a 60 inch radius. End plates 15 and 15 were /1 inch thick steel plate A.S.T.M. A-36. Bolts 21 and 25 were inch diameter A.S.T.M. A 325 in 1 inch diameter drilled holes on about 12 inch centers, spaced about 2% inches from the outside surface.

Gaskets 29 and 33 were one-half inch wide X onefourth inch thick of neoprene satisfying specification NAAMM Standard SG-lhaving a durometer less than 39 and a tensile strength in excess of 2,000 psi.

I claim:

1. In a circumferential joint for connecting adjacent arcuate metallic segments of a tunnel lining subject to jacking forces, said segments including inwardly extending flanges having opposed plane surfaces jointed together by bolts, the improvement comprising:

a. a gasket positioned between and in contact with said plane surfaces of said flanges and extending only over a portion of said surfaces adjacent the outer end of said flanges for sealing; and

b. metal-to-metal contact between said plane surfaces of said flanges in the area of said bolts, for improved joint stiffness and resistance to creep of said gasket during jacking and bolting.

2. The invention of claim 1 in which said gasket is a neoprene having a durometer less than 39 and a tensile strength in excess of 2,000 psi.

3. In a longitudinal joint for connecting adjacent arcuate metallic segments of a tunnel lining subject to jacking forces, said segments including inwardly extending end plates having opposed plane surfaces jointed together by bolts, the improvement comprising:

a. a gasket positioned between and in contact with said plane surfaces of said end plates and extending only over a portion of said surfaces adjacent the outer end of said end plates for sealing; and

b. metal-to-metal contact between said plane surfaces of said end plates in the area of said bolts, for improved joint stiffness and resistant to creep of said gasket during jacking and bolting.

4. The invention of claim 3 in which said gasket is a neoprene having a durometer less than 39 and a tensile strength in excess of 2,000 psi. 

1. In a circumferential joint for connecting adjacent arcuate metallic segments of a tunnel lining subject to jacking forces, said segments including inwardly extending flanges having opposed plane surfaces jointed together by bolts, the improvement comprising: a. a gasket positioned between and in contact with said plane surfaces of said flanges and extending only over a portion of said surfaces adjacent the outer end of said flanges for sealing; and b. metal-to-metal contact between said plane surfaces of said flanges in the area of said bolts, for improved joint stiffness and resistance to creep of said gasket during jacking and bolting.
 2. The invention of claim 1 in which said gasket is a neoprene having a durometer less than 39 and a tensile strength in excess of 2,000 psi.
 3. In a longitudinal joint for connecting adjacent arcuate metallic segments of a tunnel lining subject to jacking forces, said segments including inwardly extending end plates having opposed plane surfaces jointed together by bolts, the improvement comprising: a. a gasket positioned between and in contact with said plane surfaces of said end plates and extending only over a portion of said surfaces adjacent the outer end of said end plates for sealing; and b. metal-to-metal contact between said plane surfaces of said end plates in the area of said bolts, for improved joint stiffness and resistant to creep of said gasket during jacking and bolting.
 4. The invention of claim 3 in which said gasket is a neoprene having a durometer less than 39 and a tensile strength in excess of 2,000 psi. 